U.S. patent number 7,569,205 [Application Number 11/899,885] was granted by the patent office on 2009-08-04 for nanodiamond fractional and the products thereof.
This patent grant is currently assigned to International Technology Center. Invention is credited to Suzanne Ani Ciftan Hens, Olga Alexander Shenderova, Scott L. Wallen.
United States Patent |
7,569,205 |
Hens , et al. |
August 4, 2009 |
**Please see images for:
( Certificate of Correction ) ** |
Nanodiamond fractional and the products thereof
Abstract
In certain embodiments, a method of processing detonation
nanodiamonds to fractionate the detonation nanodiamonds involves,
in order forming a combination of detonation nanodiamonds and a
solvent, said solvent containing at least approximately 10% DMSO
(v/v), applying a dispersive technique to said combination,
subjecting said combination to a procedure that causes nanodiamond
particles of a first size range to be substantially spatially
separated from nanodiamonds of a second size range, and collecting
said nanodiamonds of said first size range essentially free of said
second size range. This abstract is not to be considered limiting,
since other embodiments may deviate from the features described in
this abstract.
Inventors: |
Hens; Suzanne Ani Ciftan
(Durham, NC), Wallen; Scott L. (Chapel Hill, NC),
Shenderova; Olga Alexander (Raleigh, NC) |
Assignee: |
International Technology Center
(Raleigh, NC)
|
Family
ID: |
40910121 |
Appl.
No.: |
11/899,885 |
Filed: |
September 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60842960 |
Sep 8, 2006 |
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Current U.S.
Class: |
423/446; 106/3;
423/263; 423/447.1; 51/307; 51/308; 51/309 |
Current CPC
Class: |
B01J
3/08 (20130101); C01B 32/28 (20170801); C09G
1/02 (20130101) |
Current International
Class: |
B01J
3/06 (20060101); B24D 3/02 (20060101); C01F
17/00 (20060101); C09G 1/02 (20060101); D01F
9/12 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2005-320220 |
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Nov 2005 |
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JP |
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WO 2007/133765 |
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Nov 2007 |
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WO |
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Other References
Sato et al.; Study on Dispersion and Surface Modification of
Diamond Powders by Ultrasound Exposure; IEEEUltrasonic Symposium;
2002. cited by examiner .
Derwent Accession No. 2007-894395 relating to WO 2007/133765 A2.
cited by other .
"Deagglomeration and functionalisation of detonation diamond," Anke
Krueger et al., Wiley InterScience, published Sep. 4, 2007. cited
by other .
"Effect of sodium oleate adsoption on the colloidal stability and
zeta potential of detonation synthesized diamond particles in
aqueous solutions," Xiangyang Yu et al, Science Direct, Diamond and
Related Materials 14 (2005) p. 206-212, Jan. 8, 2004. cited by
other .
"Influence of surface modification adopting thermal treatments on
dispersion of detonation nanodiamond," Xiangyang Yu et al, Science
Direct, Journal of Solid State Chemistry 178 (2005), p. 688-693,
Oct. 15, 2004. cited by other .
"Nanodiamonds for Biological Investigations," V.S. Bondar et al.,
Physics of the Solid State, vol. 46, No. 4, p. 716-719, 2004. cited
by other .
"Disperse Strenghtening of Polymers--Theoretical Considerations and
Experiments with UDDP," S. Stavrev et al., Nanoscience &
Nanotechnology, eds. E. Balabanova, I. Dragieva, Heron Press,
Sofia, 2001. cited by other .
"Deaggregation of Ultra-Disperse Diamond Powders," J.S. Karadjov et
al., Space Research Institute, Sep. 2006. cited by other .
"Preparation and Behavior of Brownish, Clear Nanodiamond Colloids,"
Ozawa et al., Wiley InterScience, 2007. cited by other .
"In Silico Approaches to Prediction of Aqueous and DMOS Solubility
of Drug-Like Compounds: Trends, Problems and Solutions," Konstantin
V. Balakin et al., Current Medicinal Chemistry, 13, p. 223-241,
2006. cited by other .
"Nanodiamond and onion-like carbon polymer nanocomposites," O.
Shenderova et al., ScienceDirect, Diamond and Related Materials 16,
p. 1213-1217, 2007. cited by other .
"Application-Specific Detonation Nanodiamond Particulate," O.
Shenderova et al., Nanotech, 2006. cited by other.
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Primary Examiner: Mayes; Melvin C
Assistant Examiner: Gregorio; Guinever S
Attorney, Agent or Firm: Miller Patent Services Miller;
Jerry A.
Government Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM
LISTING COMPACT DISK APPENDIX:
This invention was made with government support under U.S. Army
Research Laboratory under grant W911NF-04-2-0023.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from U.S. Provisional Application
No. 60/842,960 filed on 8 Sep. 2006 entitled "DMSO FORMULATIONS FOR
NANODIAMONDS" which is hereby incorporated by reference.
Claims
What is claimed is:
1. A method of processing detonation nanodiamonds to fractionate
the detonation nanodiamonds comprising, in order: providing
detonation nanodiamonds, forming a combination consisting
essentially of said detonation nanodiamonds and a solvent, said
nanodiamonds exhibiting a positive zeta potential in said solvent,
said solvent consisting essentially of DMSO making up at least
approximately 10% DMSO (v/v) in the solvent with any balance of the
solvent consisting essentially of a polar solvent, wherein the DMSO
increases or stabilizes the magnitude of the positive zeta
potential of the detonation nanodiamonds in the combination,
applying a dispersive technique to said combination, subjecting
said combination to a procedure that causes nanodiamond particles
of a first size range to be substantially spatially separated from
nanodiamonds of a second size range, and collecting said
nanodiamonds of said first size range essentially free of said
second size range.
2. A method for processing detonation nanodiamonds as in claim 1,
wherein said solvent contains approximately 20% (v/v) DMSO.
3. A method for processing detonation nanodiamonds as in claim 1,
wherein said solvent contains approximately 10-30% (v/v) DMSO.
4. A method for processing detonation nanodiamonds as in claim 3,
wherein said solvent is essentially DMSO, and said solvent
stabilizing or increasing the nanodiamond zeta potential as
compared to the zeta potential of the detonation nanodiamonds in
water.
5. A method for processing detonation nanodiamonds as in claim 1,
wherein said physical dispersive technique comprises ball
milling.
6. A method for processing detonation nanodiamonds as in claim 4,
wherein an additional solvent or mixture of solvents is added to
the dispersion collected following fractionation.
7. A method for processing detonation nanodiamonds as in claim 1,
further comprising deposition of nanodiamond particles of said
first size range on a solid substrate wherein the nanodiamond
particles remain affixed to said substrate, said deposition
following the collecting of said nanodiamonds of said first size
range essentially free of said second size range.
8. A method for processing detonation nanodiamonds as in claim 1,
further comprising removing the solvent from the collected
nanodiamond particles of said first size range to produce a
detonation nanodiamond product.
9. A method for processing detonation nanodiamonds as in claim 6,
further comprising deposition of nanodiamond particles of said
first size range on a solid substrate wherein the nanodiamond
particles remain affixed to said substrate, said deposition
following the collecting of said nanodiamonds of said first size
range essentially free of said second size range.
10. A method for processing detonation nanodiamonds as in claim 4,
further comprising removing the solvent from the collected
nanodiamond particles of said first size range.
11. A method for processing detonation nanodiamonds as in claim 8,
further comprising combining a polar solvent with the detonation
nanodiamond product.
12. A stable suspension of detonation nanodiamonds having a
positive zeta potential in a solvent that consists essentially of
at least approximately 10% (v/v) DMSO with any balance of the
solvent being a polar solvent and the volume-averaged size of the
detonation nanodiamonds is less than approximately 125 nm, wherein
the presence of DMSO in the solvent substantially stabilizes or
increases the magnitude of the positive zeta potential of the
detonation nanodiamonds.
13. A method for processing detonation nanodiamonds, comprising
forming a combination of detonation nanodiamonds and a first
solvent, applying a dispersive technique to said combination,
subjecting said combination to a procedure that causes nanodiamond
particles of a first size range to be substantially spatially
separated from nanodiamonds of a second size range, collecting a
suspension of said nanodiamonds of said first size range
essentially free of said second size range, and adding DMSO to said
collected suspension of said nanodiamonds of said first size range
wherein said nanodiamonds exhibit a positive zeta potential to
prevent agglomeration of the nanodiamonds during removal of the
solvent from the collected suspension, and removing the solvent
from said collected suspension of nanodiamonds of said first size
range to produce a detonation nanodiamond product.
14. A method as in claim 13, wherein said first solvent is selected
from the group consisting essentially of water, methanol and
isopropanol.
15. A method as in claim 13, further comprising combining a solvent
with the detonation nanodiamond product.
16. A method for processing detonation nanodiamonds as in claim 13,
further comprising combining a polar solvent with the detonation
nanodiamond product.
17. A method as in claim 13, wherein said collected suspension
contains at least approximately 10% (v/v) DMSO.
Description
BACKGROUND OF THE INVENTION
Nanodiamonds produced by detonation synthesis using
carbon-containing explosives as the precursor material are valuable
for diverse applications. While the primary particle size of these
detonation nanodiamonds (DND) is 4-5 nm, during processes of
synthesis and purification these particles become agglomerated and
appear as aggregates when suspended in solvents. For example, DND
aggregates in water are typically between 200 and 400 nm. In order
to utilize DND for many applications, it is important to isolate
smaller particles from larger aggregates. The current methods for
size-fractionation of DND have drawbacks including being labor
intensive. Some fractionation schemes require surface modification
of the DND, which is sometimes undesirable.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart of an Example of an exemplary method
according to certain illustrative Examples.
FIG. 2 is SEM images of the DND seeding on Si substrate performed
using four DND suspensions: 0.25% (w/v) DND in pure DMSO (S1); 0.5%
(w/v) DND in pure DMSO (S2); 0.25% (w/v) DND in the mixture of
DMSO/methanol 50%-50% (v/v) from Suspension Example XXVIII. (S3);
0.2% (w/v) DND in the mixture of DMSO/methanol 50%-50% (v/v) from
the Suspension Example IX. (S4).
DETAILED DESCRIPTION OF THE INVENTION
"DMSO" as used here is dimethyl sulfoxide.
It should be noted that certain examples included in this
disclosure represent embodiments of the invention. Certain examples
are not embodiments of the invention, but are included for
comparison to embodiments of the invention. A desired outcome of
the experiments conducted was to identify a high yielding process
with a small volume-averaged particle size in the suspension (e.g.,
less than about 50-125 nm).
DND Ch-St used in various Examples described below was produced by
detonation using ice cooling media and purified using chromic
anhydride in sulfuric acid. These DNDs have a wide range of
particle sizes. The volume-averaged particle size in water is 250
nm and the volume-averaged particle size in DMSO is 215 nm.
DND 16 was produced by purification of DND Ch-St using ion exchange
resins.
Method Example I: A mixture of 10% (w/v) DND Ch-St in DMSO was
treated for two hours in a Retsch PM400 ball milling machine. The
suspension was diluted with DMSO to a concentration of 7.5% (w/v)
DND. The sample was then centrifuged at 25,000.times.g for 30
minutes. The supernatant was retained.
Dispersion Example I: This Example is the supernatant retained in
Method Example I. In one such case, the dispersion contained 2.5%
(w/v) DND with an average volumetric size of less than 40 nm.
Method Example II: A mixture of 15% (w/v) DND Ch-St in DMSO was
treated in for two hours in a Retsch PM400 ball milling machine.
The suspension was diluted with DMSO to a concentration of 9% (w/v)
DND. The sample was then centrifuged at 25,000.times.g for 30
minutes. The supernatant was retained.
Dispersion Example II: This Example is the supernatant retained in
Method Example II. In one such case, the dispersion contained 2.7%
(w/v) DND with an average volumetric size of less than 50 nm.
Method Example III: A mixture of 1% (w/v) DND Ch-St is dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was retained.
Dispersion Example III: This Example is the supernatant retained in
Method Example III. In one such case, the dispersion contained
0.22% (w/v) DND with a volume-averaged particle size of 40 nm.
Method Example IV: A mixture of 3% (w/v) DND Ch-St was dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was retained.
Dispersion Example IV: This Example is the supernatant retained in
Method Example IV. In one such case, the dispersion contained 0.9%
(w/v) DND with a volume-averaged size of 48 nm.
Method Example V: A mixture of 1% (w/v) DND Ch-St was dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was removed. The pellet was dispersed in DMSO by ultrasonic
agitation (5 minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example V: This Example is the supernatant retained in
Method Example V. In one such case, the dispersion contained 0.18%
(w/v) DND with a volume-averaged size of 41 nm.
Method Example VI: A mixture of 3% (w/v) DND Ch-St was dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was removed. The pellet was dispersed in DMSO by ultrasonic
agitation (5 minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example VI: This Example is the supernatant retained in
Method Example VI. In one such case, the dispersion contained 0.55%
(w/v) DND with a volume-averaged size of 50 nm.
Method Example VII: A mixture of 1% (w/v) DND 16 was dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was retained.
Dispersion Example VII: This Example is the supernatant retained in
Method Example VII. In one such case, the dispersion contained
0.39% (w/v) DND with a volume-averaged size of 33 nm.
Method Example VIII: A mixture of 1% (w/v) DND 16 was dispersed in
50% (v/v) DMSO and 50% (v/v) water by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example VIII: This Example is the supernatant retained
in Method Example VIII. In one such case, the dispersion contained
0.45% (w/v) DND with a volume-averaged size of 47 nm.
Method Example IX: A mixture of 1% (w/v) DND 16 was dispersed in
50% (v/v) DMSO and 50% (v/v) methanol by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example IX: This Example is the supernatant retained in
Method Example IX. In one such case, the dispersion contained 0.2%
(w/v) DND with a volume-averaged size of 36 nm.
Method Example X: A mixture of 1% (w/v) DND 16 was dispersed in 40%
(v/v) DMSO and 60% (v/v) methanol by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example X: This Example is the supernatant retained in
Method Example X. In one such case, the dispersion contained 0.11%
(w/v) DND with a volume-averaged size of 65 nm.
Method Example XI: A mixture of 1% (w/v) DND 16 is dispersed in 30%
(v/v) DMSO and 70% (v/v) methanol by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example XI: This Example is the supernatant retained in
Method Example XI. In one such case, the dispersion contained 0.07%
(w/v) DND with a volume-averaged size of 83 nm.
It should be noted that for each of the experimental examples in
this disclosure, the specific results were for a particular batch
of DND particles. Since DND are variable from batch to batch, the
average size obtained after the method is performed would be
expected to variable. It is likely, that each method Example
disclosed here could yield average sizes approximately 50% higher
or approximately 30% lower than the actual results disclosed. For
one example, if another batch of DND particles was used, it would
not be surprising if Method Example XI yielded a volume-averaged
size of 125 nm.
Method Example XII: A mixture of 1% (w/v) DND 16 was dispersed in
50% (v/v) DMSO and 50% (v/v) water by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was removed. The
pellet was dispersed in 50% (v/v) DMSO and 50% (v/v) water by
ultrasonic agitation (5 minutes, 10 watts). The sample was then
centrifuged at 25,000.times.g for 30 minutes. The supernatant was
retained.
Dispersion Example XII: This Example is the supernatant retained in
Method Example XII. In one such case, the dispersion contained
0.23% (w/v) DND with a volume-averaged size of 56 nm.
Method Example XIII: A mixture of 1% (w/v) DND 16 was dispersed in
20% (v/v) DMSO and 80% (v/v) methanol by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 25 minutes. The supernatant was retained.
Dispersion Example XIII: This Example is the supernatant retained
in Method Example XIII. In one such case, the dispersion contained
0.07% (w/v) DND with a volume-averaged size of 75 nm.
Method Example XIV: A mixture of 1% (w/v) DND 16 was dispersed in
20% (v/v) DMSO and 80% (v/v) isopropanol by ultrasonic agitation (5
minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 25 minutes. The supernatant was retained.
Dispersion Example XIV: This Example is the supernatant retained in
Method Example XIV. In one such case, the dispersion contained 0.6%
(w/v) DND with a volume-averaged size of 80 nm.
Method Example XV: A mixture of 3% (w/v) DND 16 was dispersed in
DMSO by ultrasonic agitation (5 minutes, 10 watts). The sample was
then centrifuged at 25,000.times.g for 30 minutes. The supernatant
was retained.
Dispersion Example XV: This Example is the supernatant retained in
Method Example XV. In one such case, the dispersion contained 1.4%
(w/v) DND with a volume-averaged size of 35 nm.
Method Example XVI: A mixture of 3% (w/v) DND 16 was dispersed in
10% (v/v) DMSO and 90% (v/v) de-ionized water by ultrasonic
agitation (5 minutes, 10 watts). The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example XVI: This Example is the supernatant retained in
Method Example XVI. In one such case, the dispersion contained 0.7%
(w/v) DND with a volume-averaged size of 40 nm.
It is specifically envisioned that a wide range of dispersive
techniques could be used alternatively to ultrasonic agitation,
ball milling or other physical or other dispersive techniques.
Those methods would include, but not be limited to, shaking,
movement in electrical fields, and exposure to electromagnetic
radiation (for example, in the UV-VIS region).
It is specifically envisioned that other fractionation techniques
compared to centrifugation could be used instead of centrifugation.
Those methods could include, but are not be limited to flow
electrophoresis, gravimetric sedimentation, solvent/antisolvent of
supercritical fluids, and other methods known in the field.
It is specifically envisioned that Examples of the invention
disclosed here could work on a wide range of DND types. However,
while it may be possible for methods which are Examples of the
invention disclosed here to fractionate other DND types, those with
positive zeta-potentials seem to work best.
It is worth noting that in solvents containing DMSO and either
isopropanol or methanol, adjustment of the portion of the solvent
which is isopropanol or methanol varies the results of the
fractionation. That adjustability can be useful to allow the
results to be tailored for specific requirements.
A variety of solvents which disperse detonation nanodiamonds well,
which not containing DMSO, were tried as alternatives. However,
none performed as satisfactorily as those containing DMSO. The
effect of DMSO seems to go beyond being a "good solvent." However,
the underlying reasons for that effect are not clear. Generally
speaking, smaller volume averaged particle size in the dispersion
and (at higher yields) are considered to be most desirable.
Method Example XVII: A mixture of 10% (w/v) DND Ch-St in de-ionized
water was treated for two hours in a Retsch PM400 ball milling
machine. The suspension was diluted with de-ionized water to a
concentration of 4% (w/v) DND. The sample was then centrifuged at
25,000.times.g for 30 minutes. The supernatant was retained.
Dispersion Example XVII: This Example is the supernatant retained
in Method Example XVII. In one such case, the dispersion contained
no nanodiamond particles detectable by eye. It was not possible to
fractionate ball-milled Ch-St DND.
Method Example XVIII: A mixture of 1% (w/v) DND Ch-St is dispersed
in de-ionized water by ultrasonic agitation (5 minutes, 10 watts).
The sample was then centrifuged at 1,000.times.g for 5 minutes. The
supernatant was retained.
Dispersion Example XVIII: This Example is the supernatant retained
in Method Example XVIII. In one such case, the dispersion contained
no nanodiamond particles detectable by eye. It was not possible to
fractionate in de-ionized water Ch-St DND.
Method Example XIX: A mixture of 3% (w/v) DND 16 was dispersed in
de-ionized water by ultrasonic agitation (5 minutes, 10 watts). The
sample was then centrifuged at 25,000.times.g for 30 minutes. The
supernatant was retained.
Dispersion Example XIX: This Example is the supernatant retained in
Method Example XIX. In one such case, the dispersion contained
0.47% (w/v) DND with a volume-averaged size of 30 nm.
Method Example XX: A mixture of 1% (w/v) DND Ch-St was dispersed in
pyridine by ultrasonic agitation in a sonic bath (15 minutes). The
sample was then centrifuged at 13,000.times.g for 10 minutes. The
supernatant was retained.
Dispersion Example XX: This Example is the supernatant retained in
Method Example XX. In one such case, the dispersion contained no
nanodiamond particles detectable by eye. It was not possible to
fractionate in pyridine the Ch-St DND.
Method Example XXI: A mixture of 1% (w/v) DND Ch-St was dispersed
in dimethylformamide by ultrasonic agitation in a sonic bath (15
minutes). The sample was then centrifuged at 25,000.times.g for 30
minutes. The supernatant was retained.
Dispersion Example XXI: This Example is the supernatant retained in
Method Example XXI. In one such case, dispersion contained 0.07%
(w/v) DND with a volume-averaged size of 42 nm.
Method Example XXII: A mixture of 1% (w/v) DND 16 was dispersed in
Methanol by ultrasonic agitation (5 minutes, 10 watts). The sample
was then centrifuged at 25,000.times.g for 25 minutes. The
supernatant was retained.
Dispersion Example XXII: This Example is the supernatant retained
in Method Example XXII. In one such case, the dispersion contained
no nanodiamond particles detectable by eye. In one such case, it
was not possible to fractionate DND 16 in Methanol.
Method Example XXIII: A mixture of 1% (w/v) DND 16 was dispersed in
isopropanol by ultrasonic agitation (5 minutes, 10 watts). The
sample was then centrifuged at 25,000.times.g for 25 minutes. The
supernatant was retained.
Dispersion Example XXIII: This Example is the supernatant retained
in Method Example XXIII. In one such case, the dispersion contained
no nanodiamond particles detectable by eye. In one such case, it
was not possible to fractionate DND 16 in isopropanol.
Thus, it was not possible to fractionate DND Ch-St in pure solvents
such as water, isopropanol, methanol, or pyridine. It was possible
to fractionate DND Ch-St in dimethylformamide but the yield of
small size fractions was low. While DND 16 can be easily
fractionated in water, the yield of the fraction of similar size in
DMSO is several times higher at equal conditions of
fractionation.
Thus, in certain Examples, as depicted in FIG. 1, a method depicted
as 100 for fractionating denotation nanodiamond starts at 102 and
involves in order forming a combination of denotation nanodiamonds
and a solvent at 106 which contains at least approximately 10%
(v/v) DMSO, applying a dispersive technique to the combination at
110, centrifuging the combination to form supernatant and deposited
precipitate at 114, and collecting the supernatant essentially free
of the deposited precipitate at 120.
Fractionated DND can be produced by any of the variations in the
method as described above.
Surprisingly, removal of the solvent from the supernatant collected
following fractionalization of DND in DMSO, subsequent solvent
removal from the DND product, followed by re-dispersing this DND
product in DMSO and other solvents did not result in agglomeration.
Surprisingly, in a variety of solvents the particle size of the
re-dispersed DND product was similar to the size in the initial
fraction of DND in DMSO. In contrast typical DND products produced
by drying a water suspension, followed by re-dispersion in water
results in a particle size that is typically noticeably larger. DND
in powder form is much easier and more economical to transport than
suspensions and it allows for flexibility in formulating new
suspensions. Below are illustrations of certain Examples of the
method.
Method Example XXIV: The supernatant of 16 in pure DMSO retained in
Method Example XV was dried by heating.
Material Example XXIV: This Example is the powder collected in
Method Example XXIV. To determine properties of that material, the
powder was re-suspended in DMSO by shaking. All of that powder was
completely dispersed in DMSO. The volume-averaged particle size in
the suspension after shaking was 60 nm. Then the suspension was
sonicated. After sonication the volume-averaged particle size, 35
nm, became similar to that of the suspension before drying. In
another experiment, a sample of Example XXIV was re-suspended in
pure water and sonicated. After sonication the volume-averaged
particle size in water became similar to that in the suspension
before drying, 37 nm. In another experiment, a sample of Example
XXIV was re-suspended in DMSO. Then sufficient methanol was added
so that the solvent was 1:10 (v/v) DMSO:methanol. After sonication
the volume-averaged particle size in the suspension was 50 nm.
Method Example XXV: the supernatant of 16 in de-ionized water
retained in Method Example XIX was dried by heating.
Material Example XXV: This Example is the powder collected in
Method Example XXV.
The powder collected in the material Example XXV was re-suspended
in pure water by shaking and was then sonicated. The suspension had
noticeable residue. The volume-averaged particle size in the
suspension was 98 nm. This size is larger than the size of DND in
the initial de-ionized water suspension before drying.
Method Example XXVI: The supernatant of 16 in 10% (v/v) DMSO and
90% (v/v) de-ionized water obtained in Method Example XVI was dried
by heating.
Material Example XXVI: This Example is the powder collected in
Method Example XXVI.
The powder collected in Material Example XXVI was re-dispersed in
pure water by shaking and then sonicated. The suspension had some
residue. The volume-averaged particle size in the suspension was 55
nm.
Method Example XXVII: The supernatant of 16 in de-ionized water
obtained in Method Example XIX was mixed with equal amount of DMSO
by volume. The suspension was shaken and dried by heating.
Material Example XXVII: This Example is the powder collected in
Method Example XXVII.
The powder collected in material Example XXVII was re-suspended in
water by shaking and then sonicated. The suspension had some
residue. The volume-averaged particle size in the suspension was 48
nm.
When a DND fraction from a water suspension is dried to a powder
form and then re-suspended in de-ionized water, the volume averaged
agglomerate size might increase up to 100%. However, in certain
Examples of the invention, drying fractionated DND from pure DMSO
followed by reconstitution in DMSO, the reconstituted DND had
approximately the same particle size. The same was true when those
dried DND were reconstituted in some other solvents. In other
Examples of the invention, drying DND from some solvents which are
a mixture of DMSO and other solvents, the re-suspended DND
particles have less than a 50% size increase.
The suspensions and powders of fractionated DND obtained by using
DMSO are useful in a variety of applications, including but are not
limited to suspensions for seeding of DND for growth of CVD diamond
films; formulations of ND in DMSO for electronic processing
methods, such as photoresist stripping, substrate polishing,
substrate cleaning; formulations of DND in DMSO for paint removal
and cleaning of substances; formulations of DND in DMSO for
chemical mechanical polishing and other applications.
Certain Examples of the invention illustrating applications are
provided below. In certain Examples of the invention addition of a
second solvent to the suspension of DND fraction in pure DMSO
following fractionation of DND in pure DMSO was found to be
beneficial for some applications.
Method Example XXVIII: the supernatant of 16 in DMSO obtained in
Method Example XV was mixed with methanol and additional DMSO so
that the final solvent mixture was 1:1 (v/v) DMSO:methanol.
Suspension Example XXVIII: This Example is the suspension of 0.25%
(w/v) DND obtained from Method Example XXVIII.
Comparative seeding experiments were done for four DND suspensions:
0.25% (w/v) DND in DMSO obtained using dissolved suspension from
the Suspension Example XV (S1); 0.5% (w/v) DND in pure DMSO
obtained using dissolved suspension from the Suspension Example XV
(S2); 0.25% (w/v) DND in the mixture of DMSO/methanol 50%-50% (v/v)
obtained from the Suspension Example XXVIII. (S3); 0.2% (w/v) DND
in the mixture of DMSO/methanol 50%-50% (v/v) from the Suspension
Example IX. (S4). Silicone substrates were immersed in the
suspensions S1-S4 and treated in a sonication bath within 10
minutes. After that the substrates were rinsed with methanol and
nitrogen-dried. Results of the seeding are illustrated in FIG. 2.
The best results (deposition of smaller sizes of DND aggregates on
the substrate, better uniformity of the seeding and higher density
of the seeds) are observed for the sample S3. In the other Examples
of the invention experiments were performed for other substrates,
such as stainless steel, titanium, tungsten, glass and quartz. Good
quality seeding of DND over the substrates was obtained. In another
Example of the invention, 0.12% (w/v) DND in the mixture of
DMSO/methanol 25%-75% (v/v) was used for seeding on a Si substrate
and good seeding results were obtained.
Thus in certain Examples of the invention adding a second solvent
to the suspension of DND fractionated in DMSO results in a material
Example that provided the best results for some applications.
Experiment 1
Separating differently sized particles using purified 16 ND was
completed in a "bottom-up" approach starting at low speeds and
ending at high centrifugation speeds, removing the largest
particles while the remaining smaller fractions are left in the
supernatant at the end of processing. To obtain the smallest
fractions in a more rapid manner, a "top-down" approach may be used
with an initial high centrifugation speed to collect the smallest
particles in the supernatant. Initial work on this "top-down"
approach showed that similar particle sizes were collected using
water and DMSO suspensions for 16, while ethanol suspensions
produced larger particle sizes. The small particle yield was lowest
for ethanol and highest for DMSO. In addition, the small fraction
yielded 5 nm particles, as observed by scanning electron
microscopy, in this one-step fractionation approach.
The second set of experiments entailed a detailed analysis of the
total yield of small particles as a function of ND material and
solvent formulation. Below are the details of the processing steps
for each sample with the accompanying data in Table I.
In order to rigorously test the capability of a suspension medium,
the crude Ch-St is used for stability, yield, and particle size
measurements. Water and DMSO suspensions produced very different
results: A 1% Ch-St suspension in water produced large particles
(250 nm) that rapidly sedimented, so that it was not possible to
fractionated Ch-St in water, whereas small particles (50-65 nm) and
stable suspensions were obtained for 1% Ch-St in DMSO by
centrifugation the suspension with polydispersed powder for 30
minutes at 25,000 g see Table I. The yield of small particles from
the Ch-St material will be compared to the yield of the same from
the purified 16 product. The product loss in going from Ch-St to 16
was 50%. Thus, if this processing can be eliminated the product
would be less expensive and time consuming to prepare.
Interestingly, observation of the pellet formed from a highly
concentrated solution, 5% Ch-St in DMSO, showed a rusty red color
at its center, which we suspect is insoluble iron oxide. Treatment
in DMSO can provide purification of Ch St from metallic impurities
and large nanodiamond agglomerates.
TABLE-US-00001 TABLE I Comparison of particle size and yield for
different solvents and concentrations. 1.sup.st round and 2d round
correspond to centrifugation of the suspensions within 30 minutes
at 25,000 g. For the 2d round, pellets obtained in the 1.sup.st
round were resuspended and centrifuged again. 1.sup.st Round
2.sup.nd Round Solvent (initial Size (unimodal Size (unimodal
concentration) % ND [volumetric]) Yield [volumetric]) DMSO 1% 16 54
nm [33 nm] 3.92 mg/mL 65 nm [34 nm] (0.39%) DMSO-H2O 16 65 nm [47
nm] 4.54 mg/mL 80 nm [56 nm] (50-50) 1% (0.45%) DMSO-Methanol 16 50
nm [36 nm] Lower 51 nm [35 nm] (50-50) 1% (w.r.t 100% DMSO)
DMSO-Methanol 16 65 nm Low (40-60) 1% DMSO-Methanol 16 83 nm Very
Low (30-70) 1% DMSO-Methanol 16 >>80 nm Very low (20-80) 1%
DMSO 1% Ch-St 61 nm [40 nm] 60 nm [41 nm] DMSO 3% Ch-St 59 nm [48
nm] 59 nm [50 nm] DMSO 5% Ch-St Stable.dagger. DMSO 12% Ch-St
Stable.dagger. H2O 12% Ch-St DNW DMSO-Methanol Ch-St DNW (50-50) 1%
H2O 1% Ch-St DNW Acetone 1% 16 DNW Methanol 1% 16 183 nm [280 nm]
DMSO-Acetone 16 DNW (50-50) 1% DNW (did not work): all the ND
condensed into the pellet leaving no ND in the supernatant
.dagger.Fractionation of these solutions was not attempted and may
not be possible (for 25,000 g) because of their high viscosity.
After the first round of centrifugation, the pellet was dispersed
again in the solvent and fractionation was repeated (second round).
Based on the visual size of the pellets after centrifugation of 16
in water and DMSO at the same initial concentrations, it was
concluded that DMSO provides higher yields of the smallest
particles (with approximately the same particle size after
centrifugation under the same-conditions). Another advantage of
using DMSO for fractionation of Ch 16 is that higher initial
concentrations can be obtained in DMSO. We tried concentrations up
to 10% which resulted in .about.2% concentration in the
supernatant, a high concentration. As can be seen from the table,
processing in mixtures of DMSO with several other solvents resulted
in suspensions with small particle sizes.
From the above description and drawings, it will be understood by
those of ordinary skill in the art that the particular Examples
shown and described are for purpose of illustration only, and are
not intended to limit the scope of the invention. Those of ordinary
skill in the art will recognize that the invention may be embodied
in other specific forms without departing from its spirit or
essential characteristics. References to details of particular
Examples are not intended to limit the scope of the claims.
Thus, in certain embodiments, a method of processing detonation
nanodiamonds to fractionate the detonation nanodiamonds involves,
in order forming a combination of detonation nanodiamonds and a
solvent, the solvent containing at least approximately 10% DMSO
(v/v), applying a dispersive technique, such as a physical or
chemical dispersive technique, to the combination, subjecting the
combination to a procedure that causes nanodiamond particles of a
first size range to be substantially spatially separated from
nanodiamonds of a second size range, and collecting the
nanodiamonds of the first size range essentially free of the second
size range. In certain embodiments, the solvent contains at least
approximately 30% (v/v) DMSO. In certain embodiments, the solvent
contains at least approximately 50% (v/v) DMSO. In certain
embodiments, the solvent is essentially DMSO. In certain
embodiments, the physical dispersive technique comprises ball
milling. In certain embodiments, an additional solvent or mixture
of solvents is added to the dispersion collected following
fractionation. In certain embodiments, the method further involves
deposition of nanodiamond particles of the first size range on a
solid substrate, the deposition following the collecting of the
nanodiamonds of the first size range essentially free of the second
size range. In certain embodiments, the detonation nanodiamonds
have a positive zeta-potential. In certain embodiments, the method
further involves removing the solvent from the collected
nanodiamond particles of the first size range to produce a
detonation nanodiamond product. In certain embodiments, the method
further involves deposition of nanodiamond particles of the first
size range on a solid substrate, the deposition following the
collecting of the nanodiamonds of the first size range essentially
free of the second size range. In certain embodiments, the method
further involves removing the solvent from the collected
nanodiamond particles of the first size range. Products consistent
with certain embodiments may include detonation nanodiamonds and
DND products processed by any of these methods.
In certain embodiment, a suspension of detonation nanodiamonds is
produced in a solvent in which the solvent contains at least
approximately 25% (v/v) DMSO and the volume-averaged size of less
than approximately 125 nm.
In certain embodiments, a method for processing detonation
nanodiamonds involves forming a combination of detonation
nanodiamonds and a first solvent, applying a dispersive technique
to the combination, subjecting the combination to a procedure that
causes nanodiamond particles of a first size range to be
substantially spatially separated from nanodiamonds of a second
size range, collecting a suspension of the nanodiamonds of the
first size range essentially free of the second size range, and
adding DMSO to the collected suspension of the nanodiamonds of the
first size range. In certain embodiments, the first solvent is
selected from the group consisting essentially of water, methanol
and isopropanol. In certain embodiments the method further involves
removing the solvent from the collected suspension of nanodiamonds
of the first size range to produce a detonation nanodiamond
product.
No claim element herein is to be construed under the provisions of
35 U.S.C. .sctn. 112, sixth paragraph, unless the element is
expressly recited using the phrase "means for" or "step for." The
terms "a" or "an", as used herein, are defined as one or more than
one. The term "plurality", as used herein, is defined as two or
more than two. The term "another", as used herein, is defined as at
least a second or more. The terms "including" and/or "having", as
used herein, are defined as comprising (i.e., open language).
Reference throughout this document to "one Example", "certain
Examples", "an Example" or similar terms means that a particular
feature, structure, or characteristic described in connection with
the Example is included in at least one Example of the present
invention. Thus, the appearances of such phrases or in various
places throughout this specification are not necessarily all
referring to the same Example. Furthermore, the particular
features, structures, or characteristics may be combined in any
suitable manner in one or more Examples without limitation. The
term "or" as used herein is to be interpreted as an inclusive or
meaning any one or any combination. Therefore, "A, B or C" means
"any of the following: A; B; C; A and B; A and C; B and C; A, B and
C". An exception to this definition will occur only when a
combination of elements, functions, steps or acts are in some way
inherently mutually exclusive.
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